Furnace apparatus



J. E. BELL FURNCE APPARATUS Filed sept. ,16. 1922 Patented July, is, 1921'.

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This invention relates to furnace apparatus for boilers and the like and it is especially useful in connection with stationar boiler installations burning pu1verizedfue 5 One of the primary objects'of my invention is to provide .an improved means. for

protectingl the refractories, particularl the rear or bridge wall of the combustion c amber against erosion.

i Another object of my invention is to provide an improved arrangement of water screen for rotectin the rear or bridge wall of the com ustion c amber.l J More specifically, my invention is directed l5 to an improved manner of connecting cooliugvcreens in a boiler` of the Stirling type. e foregoing, together with such; other objects as may hereinafter a pear, or are in cident to my Invention I o tain by means of a construction which I have illustrated in preferred form in the accompanying drawmg, wherein:

Fig. 1 is a cross section through a furnace for a Stirlin boiler, burning pulverized fuel, in whicb 'the application of my improvements is illustrated; and Fig. 2 is a section taken on the line 2 2 of Fig. 1.

Referringnow to the drawing, the com`` bustion chamber A is substantiall .of the vertical type havin an outlet or exit `for the hot products of com ustion in its upper part, indicated by the reference number 7. EX- tending over the outlet and arranged in the path of the hot gases are a plurality of banks .'45 of tubes a, b, c of a Stirling boiler.` These banks of tubes'are connected at their lower ends with the mud drumz8, and the upper ends of thetubes of each bank are connected to a drum 9. The banks of tubes may be 4o baiiiedv in any suitable manner.

The pulverized .fuel is introduced intothe combustion chamber,l preferably in a vertically downward direction by means'of one or more burners B, located n the incoming fuel adjacent the front wall 10 olf the combustion chamber. About ten .per cent of the air neededfor combustion is supplied through the burner mechanism, the remainin air needed for combustion beau ing supplied through the damper controlled auxiliary air inlets 11 in the front wall 10, such inlets communicating with channels 12 in the walls of the combustion chamber' whereby, il desireil.l the auxiliary air may w be preheated.

so as to discharge The fuelV and flame stream takes a U- shaped course through the combustion chamberto the outlet, the size of the combustion chamber being such thatcomplete combustion is had therein. The bend or base of the U -is above the floor or bottom -13 of the combustion chamber, and-the refuse not carried along in the fuel and iiame stream` in suspension, gravitates land deposits on the bottom 13'in ash form.

The temperature of the ash deposit is kept substantially below the fusion or slag' Glngpoint by means of a water screen C Iljoeated in the bottom of the combustion chamber and comprising two-sets of tubes 70 14 andy 415. These tubes are oppositely inclined, the tubes 14 being connected at theirI rear ends into a header 16 and at their front ends into a lheader 17, while the tubes 1 5, at the front, are connected into the header 17 75 and at "the rear into the header 18. The

' header 16 1s connected with the muddrum 8 by means of a plurality -of pi s 19,.pref erably arranged in groups of t ree each at the ends of the header 16. f The number of 8( these pipes, however, may be varied as the` demands of the particular installation may require. The upper ends of the pipes 19 project just above the bottom of the mud drumv 8'so as lto clear mud and scale which 8.5 'l

may collect therein. The header 18 is connected with the mud drum 8 similarly by two .groups of tubes 20,- preferably three in number for each group. vThe upper ends of the tubes 20, however, extend'well toward 90 the topof the mud drum. [A circulation is thus had through the water screen C and the 'screen operates to reduce the tempera-v ture of the deposit by absorbing radiant heat therefrom. 95 The header 17 is preferably anchored and f expansion' of' the :water 'screen tubes takes place toward the rear. In order to prevent washing away of the rear or bridge wall 21 by the meltin and` 100 running -down of the deposit thereon, .provide a cooling screen D composed ofrtubes 22, the lower 'ends of whichare connected into the header18 and the upper ends connected into the mud drum. The tubes 22 are 105 bent as illustrated, and therefore, expansion and contraction 'are automatically taken care ci.. n

Circulation takes place through the screen D and it functions to 'coolithe deposit `on 11a the rear Wall which deposit builds out in 'when the whiskers perature the forni ot' LWhisker-si or threads. This deposit, it cooled, will naturally break oll ciently to cause breaking oill by their overhunmT weight. The tubes are spaced suliciently Jfar trom the bridge wall lto permit the deposit to tall :freely to the bottom. The deposit between tubes will, ot course, fall to the bottom.

In addition to preventing' the formation ot slag, the screens 4increase the etliciency of the 'furnace in the generationotl steam and While, o'f course, they have a chilling etlect, the lowering` of temperature in the combustion chamber is a. usetul one as it results trom the absorption et heat which is employed in generating steam. The need ot employing excess air is avoided in which connection it is to be pointed out that the use of excess air lowers the furnace tem `to no useful purpose and increases the volume ot gas which must be handled and imposes limitations on the efficiency and C()2 attainable, which limitations maybe exceeded Where cooling screens are employed.

The arrangement is simple, the parts are easy to install and are readily accessible.

The tubes 20, which are tew in number, relieve the header .18 ot'some of the steam created in the lower screen C, lwhereby less steam in proportion to water enters the tubes Q2 'from the header 18.

Other advantages will occur to those skilled in the art.

What I claim is:

1. In combination with a, furnace and its boiler, a combustion chamber; a cooling screen exposedto radiant heatin` the lower portion oi the combustion chamber comprisingiwosets ot tubes, a header with which both sets are cminccted at one end, and a header tor the other end ot each set; means connecting; the last mentioned tivo headers ,into the circulation ot the boiler; and a cooling` screen lexposed to radiant heat adjacent a vertical Wall of the combustionchamber connected with one ot the headers and with the boiler.

2. In combination with a furnace and its boiler, a combustion chamber; af cooling .screen exposed to radiant heat in the lower portion ot' the combustion 'chai'ubei comprising tiro sets of oppositely inclined tubes, a header with which both seis are connected at one end, and a header t'or 'the opposite endof each set; means conueetine` the last inentionedtwo headers into .the circulation ot the boiler ;i and a cooling screen exposed to radiant heat adjacent a vertical Wall chamber connected with one of said last two headers and Withtiie boiler.

3. In combination with furnace and have built out suili-v of 1 the readme b'oil'er,v afco'inbustioti 1 i screen exposed to radiant heat in thel lower portion ot the combustion chamber comprisscreen exposed toradiant heat inthe lower,

portion of the combustion 'chamber composed ot ltubes and headers and connected in the circulation ottheboiler: and a second coolinfr screen exposed to radiant heat connected with one ot said headers and Withthe boiler.y

5. In combination with a furnace-audits boiler, a combustion chamber; a cooling screen exposed to radiant heat inthe-lower portion ot' the combustionchamber composed of tubes andiheaders. -and connected in the.

vcirculation otthe boiler-g and-a Second cooling screen exposed toiadiantheat-.connected with one olf/said header-sand with the boiler, said tubes being bent...l

susV

G. In combination with a furnace andits-I boiler, a combustion ffchainber; cooling screen. exposed to radiant heatiinL theA lower .portion ot the combustion chamber composed ot tubes and headersaind connected [inthe circulation ot' the boiler and a second cooling.r screen exposed to. radiant heat. connected with one ot said headersand lWitlzifthe boiler, said tubes being' bent and one-ot saidheaders being ancliored.-,

IUD

7. In 'combination a; boiler.; .and-itsfturnacefv said boiler having alower drum and annp per drum and a pluralityotltubes connectingr said drums, a rorw'otrelatively closclyspaoed water tubes extending` along an upright wall of the furnace and exposedtoradiant heat, downcom'er ,means-leading from theiloiier drum ot the boilerffor snpplyinggsaid ltubes with water, said tubes',y beingLconnectedat their upper ends-.'to-deliyer into-,the said lower drum otthe boil 1,-,

8. In combination a;y oilei said boiler liar-ingr` a lon er rality ot supper drums. ,and tubes .connecting fthe itl-Pl' i lower drinn, 'a ront spaced water tubes ex ...a plurality kof uis njith Ithe radiant heat, dmvncon the lower drumoY t ,said tubes-r` .with irate nected at th ,'.ipijier em said loir (trani ot.;

In; testimonybereut, signed my l deliiierfinto the orier.

have hereunto 'Jona jaren.,

and4 itsy` furnace, i A I y 

